A study published today in Cell Reports reveals an unexpected relationship between herpes simplex virus-1 (HSV-1) and Alzheimer’s disease, suggesting that some hallmark features of the disease may initially serve as a defense mechanism against viral infection.
University of Pittsburgh researchers found that tau protein, typically viewed as harmful in Alzheimer’s disease, might actually protect brain cells during early viral infections. “Our study challenges the conventional view of tau as solely harmful, showing that it may initially act as part of the brain’s immune defense,” explains senior author Or Shemesh, Ph.D., assistant professor in the Department of Ophthalmology at Pitt.
Using miniature brain models in petri dishes, the research team demonstrated that HSV-1 infection could alter levels of tau protein, activating a protective mechanism that reduced the death rate of human neurons. This finding adds a new dimension to our understanding of Alzheimer’s disease progression.
The scientists identified HSV-1-related proteins in brain samples from Alzheimer’s patients, with higher concentrations found in regions particularly vulnerable to the disease. These viral proteins appeared alongside tangles of phosphorylated tau – one of the hallmarks of Alzheimer’s pathology – across different disease stages.
While the exact mechanisms linking HSV-1 to Alzheimer’s disease remain unclear, Shemesh and colleagues are already planning future research to explore potential therapeutic strategies. Their work will focus on targeting viral proteins and fine-tuning the brain’s immune response, with possible implications for treating other neurodegenerative diseases like Parkinson’s disease and ALS.
The research team included scientists from multiple institutions, with expertise spanning ophthalmology, neuroscience, and virology. Their collaborative effort, funded in part by the National Institute of Allergy and Infectious Diseases, suggests that understanding viral infections’ role in neurodegeneration could open new avenues for treatment.